Bypass of Primary Stroke Centers Compared With Secondary Transfer for Endovascular Thrombectomy

Background: Our stroke network operates a hybrid organizational structure, with patients with potential large-vessel occlusion taken to the local primary stroke center (PSC) during office hours, and directly bypassed to the endovascular thrombectomy-capable stroke center (EVT-SC) after hours. We aimed to compare the 2 methods of transfer. Methods: Consecutive patients with anterior large-vessel occlusion treated with EVT between August 2017 and February 2021 were identified. Patients who had EVT puncture within 6 hours of last known normal were included for analysis. Patients were grouped into method of presentation: direct bypass to EVT-SC ("EVT-SC direct") or taken to local PSC with secondary transfer to EVT-SC ("PSC-transfer"). The primary outcome was 3-month functional independence (modified Rankin scale score 0-2). Secondary outcomes included mortality at 7 days and at 3 months. Results: A total of 259 patients (109 women; mean +/- SD age, 66.8 +/- 15.2 years) were included; there were 91 (35.1%) EVT-SC direct and 168 (64.9%) PSC-transfer patients. The EVT-SC direct patients had shorter median times from last known normal to thrombolysis (120 versus 147 minutes; P=0.004) and puncture (190 versus 230 minutes; P<0.001). Multivariable logistic regression analysis found that EVT-SC direct patients had greater 3-month functional independence (odds ratio [OR], 2.04 [95% CI, 1.12-3.73]; P=0.02) and lower 3-month mortality (OR, 0.33 [95% CI, 0.12-0.91]; P=0.03). For every 100 patients directly bypassed to EVT-SC, there were 14 more patients functionally independent and 9 fewer who had died, at 3 months. Conclusions: In this comparison of 2 organizational paradigms in patients with a PSC as the closest stroke center, direct bypass to EVT-SC resulted in significantly better process times and clinical outcomes compared with secondary transfers from PSCs.